Two language-related items crossed in the Information Supercollider today: the first was Tom's commentary on an opinion piece by Robert Crease and Alfred Goldhaber, the second Steven Pinker on the badness of academic writing.
All of them are worth reading, and I only have small dissents to offer here. One is that, unlike Tom and Crease and Goldhaber, I'm actually just fine with the popular usage of "quantum leap" for a particularly dramatic change. Yes, I realize that the canonical "quantum jump" is the smallest possible change, but I think that's putting too much emphasis on only one aspect of the definition. Quantum jumps in AMO physics aren't defined just by their smallness but by their discontinuity-- the change from one state to another is instantaneous, or nearly so. It's also a qualitative change, generally from one allowed state of a system to another, orthogonal state. The energy difference between the two states may be the smallest allowable, but given that the overlap between the two endpoints is (usually by definition) zero, I think it's fair to use that as an analogy for a drastic change in whatever.
Regarding Pinker's analysis of academic writing, I agree with a lot of what he says, but disagree slightly with his complaints about "metadiscourse" and excessive signposting-- all the "The previous section did this, the following section will do that" material that is so common in academic writing. While I agree this can be overdone-- signposting the structure of a short paper is sort of like having an outline slide in a ten-minute talk, a waste of space you could've filled with additional useful information-- I think he's falling into the same trap as a lot of people who give advice about talk and slide design, namely forgetting the secondary audience.
Pinker's advice is excellent if you work under the assumption that the reader is sitting down with a paper and reading it like a report to the Red King: beginning at the beginning, and not stopping until the end. While those readers are, in some senses, the ideal, much of the time we don't have the luxury of reading a paper start to finish. Academics are frequently skim-reading, looking for some particular bit of information or analysis, and the signposts Pinker complains about are an essential service for the secondary audience of skim-readers. In fact, learning to do this sort of reading is an essential part of learning How to Read in College, as Timothy Burke notes. Particularly in a longer paper, having the occasional "The previous bit was this, the next bit will be that" is incredibly useful to people who are dipping in every few pages trying to find that one number or half-remembered choice quote.
Yes, this could be done more elegantly, but the smoother and more conversational transitions of the style Pinker favors are also a little harder to spot if you're skim-reading. A little formalized language, even if it's a bit stuffy, can be worth a minor annoyance to cover-to-cover readers if it makes life significantly easier for the secondary audience of skim-readers.
(There's also the Jedi Mind Trick effect at play in some of this. That is, blatantly asserting "In the previous section, I have shown this, in the following section I will show that" can help create an impression that you have, in fact, shown this and that, simply by frequent repetition. You'd think a cognitive scientist would be wise to that...)
Anyway, these are, as I said, relatively minor complaints; I definitely recommend reading all the pieces at those links. And I'll take a look at the books by Crease and Goldhaber and Pinker from which their pieces were derived, because they sound interesting.
I'm with you on both dissents. The point of a quantum change is that it is not only discontinuous, but not even approximately continuous. The change between states may be small as viewed in the classical world (which is why classical physics works, when it does), but often you are dealing with situations where the change is large compared to the energy content of the system. That's especially true in undergraduate level quantum physics classes.
As for signposting, there are many cases in scientific writing where you are expected to do it. For instance, if you derive equation (17) by substituting equation (10) into equation (16), you are expected to say so. Many readers will accept this Jedi mind trick, but anybody who wants to check your derivation can do so. And at least in my field, it is common to lay out a roadmap at the end of the introduction, particularly in a longer paper, so that the reader who is looking for a certain piece of information will know which section to skip to.
I'll take any approximately correct use of quantum hop/skip/jump over the engineer's analogue, the "step change". Just ugh.
As for signposting, there are many cases in scientific writing where you are expected to do it. For instance, if you derive equation (17) by substituting equation (10) into equation (16), you are expected to say so.
This seems to be more a complaint about an ingrained habit. Try printing out this, and then see if you can remember where the key quantities in section 4.1 were defined.